Switching device.



E. F. HAIVHLL.

SWlTCHlN'G DEVICE.

APPucATloN FILED MAR18,1915.

1 ,2 1 8,552 PatentedA Mar. 6, 1917.

2 SHEETS-SHEET l.

E. F, HAMILL.

SWITCHING DEViCE.

APPLICATION FILED MAR.18.1915.

1,21 8,552'. Patented Mar. 6, 1917'.

2 SHEETS-SHEET 2.

UNITED STATES OFFICE.

EDWARD F. Hanna., or ciIIcAGo, ILLINOIS.

SWITCHING DEVICE.

Specication of Letters Patent.

Patented'Mar, 6, 1917.

Application led March 18', 1915. Serial No. 15,377.

. ing devices known as silent call wall switches for hospitals, although of course my inven- A tion is applicable to other uses.

When my invention is applied for hospital purposes it is designed to be controllable by a patient, for: instance, in a manner to establish a signal which may call a nurse, which signal must be established in several different places. A signal, for instance, -must be given over the door of the room so that the nurse on the floor need not go back to the headquarters before responding, and in many cases a pilot signal must be operated at some central point to indicate any group of substations from which a call might have originated.

One of the main objects of the invention is to provide a switch of this character which will operate with the very least accompaniment of noise, thus not to disturb the patient. AV further object of the invention is to provide switching mechanism which may be of the wiping character to thus insure its positive actuation at all times.

It is of course essential in devices of this kind that the patient be called upon merely to actuate a push button in order to operate the switching device. Thus an electromagnet is used to actuate the switching element, and my invention concerns itself particularly with the constructional features of this electromagnet and the particular manner ofoperating devices interposed between the l electromagnet and the switching element.

Furthermore my invention concerns itself with constructional features of the entire switching device, all as will presently appear from the detailed description of one embodiment thereof set forth in the accompanying drawings in which- Figure 1 is a front view of my improved device showing the push buttonV together with the attachment plug;

Fig. 2 is an enlarged side view of my improved device with the cover plate in section;

Fig. 3 is a. rear view of my improved device with the rear cover removed;

Fig. 4 is a longitudinal sectional view through the center of the device; Fig. 5 is a sectional view on line a-a of Fig. 3; y

ig. 6 diagrammatically illustrates one form of circuit connections for which my device is adapted, and

Figs.'7, Sand 9 are fragmentary sectional views respectively on lines c, l) and d.

My improved device includes a front plate 1 preferably-of metal having holes 2, 2 adapted to accommodate screws for attaching the front plate to the wall; rearwardly of this front plate an insulating block 3 is fastened through the agency of the screws 4, metallic bushings 5 being interposed which are molded into the block 3. A restoring button 6 projects from the front plate whose purpose will presently appear.v

Two jack thimbles 7, 7 project throu h the front plate, being fastened to the bloc 3 by being riveted over contact springs 8. The jack thimbles 7 are surrounded by insulating bushings 9 so that these jack thimbles are insulated from the plate 1. These jack thimbles are adapted to coperate with contact lingers 10, 10 mounted on the insulating block 11, thus forming a plug, a 'suitable flexible cord 12 being fastened to said plug and having conductors extending respectively into electrical contact with said fingers 10, 10. The cord terminates ina push button device 13 having the push button 14 as well understood. The contact lingers 10, 10 are split asshown, thus to serve better the purpose of making contact with the jack thimbles 7. The insulating block 3 also has internally screw threaded screws 16, the opposite end of the said cover having the hole 18 interlock with the screw 19, thus firmly securing the parts in position. The screw 19 is desirably mounted upon an upwardly projecting arm 20 forming partv of the heel piece 21 which magnetically unites the two cores of the solenoid iso vcoils 22, 22. IlFhe solenoid cores terminate asv shown more clearly -in Figs. 2 and 4 in pole pieces-23 which are of the truncated pyramidical form. 'llhese particular ,pole pieces thus coperate electromagnetically with great eiiciency with the armature 24 ot' the entire electroma net consisting of the two soleno-ids 22. his armature 24 has holes 25 through which the polar extensions 23 are adapted to pass. By virtue of the flaring form of these pole pieces the pivoted armature is maintained in association with these pole pieces with a practically constant air gap irrespective of the position ot' said armature. In order to support the armature l provide an arm 26 ot' non-magnetic material held in place on top of the solenoids through the agency of the locking ring 27, which rings are held in place by the polar extensions 23, the polar extensions preferably having screw threaded engagement with the core of their corresponding solenoids. extending arms 27 which carry the shaft 28, which shaft pivotally carries the bearing arm 29 riveted by means of the rivet 30 to the said armature 24. The rivet 30 also holds in position a flexible lift spring 31 which at its lower extremity (Fig. 4) is normally tending to move away from the corresponding extremity of the armature 24. rllhe armature is designed to actuate a plunger 32, which plunger is rigidly fastened to a. screw 33. The construction of this plunger will be more readily apparent from Fig. 4 where this plunger consists of an insulating sleeve 34 carrying a conducting ring 35, which conducting ring is locked in place by an insulating ring 35. A nut 37 is then provided upon the screw 33 having a coperating Washer and a second nut 38 with a coperating washer also screw threadedly engaging the screw 33, in cooperation with the nut 37, fastens all of the parts thus enumerated securely together. The screw 33 is slidable within a bushing 39 so that the plunger may be moved to the right or left (Fig. 4) in accordance with the movements of the armature 24. The purpose of the spring 31 it may be pointed out is to permit the armature 24 to make a slight movement in response to the solenoids 22 whereby the armature attains a certain speed of movement before it is encumbered with the drag caused by moving the plunger 32. The spring 31 thus yieldingly serves to associate the plunger and the armature together, the spring 31 preventing the loud click which would otherwise happen if this spring were not pressed, and which in a hospital is undesirable.

Thus whenever the patient operates the push button, the armature 24 is attracted and the plunger 32 (Fig. 4) is moved from right to left. Now in order to restore this The arm 26 has downwardly intatta plunger the restoring button (i comes into play. lhis restoring button has a rod 40 slidingly mounted in the block 3, which rod is encircled by a spring 4l. rlihis spring 4l normally pushes the restoring button and rod to the left (Fig. 4). The rod 40 is of course of non-magnetic material, passes through the heel piece 2l, and also nds a sliding bearing in the element 26.

lt will thus be seen that should the armature 24 be in au attracted position, that in order to restore it to the position of Fig. 4, all that is necessary is to push in the restoring button G and the parts will again assume the position occupied in Fig. 4. The plunger 32 by reason of its conducting ring controls the circuit through a plurality of switching springs. These switching springs respectively 42, 43, 44, 45, 46 and 47 are mounted upon an insulating block 3, through the agency of screws as readily apparent.

Y These switching springs are in general of the shape'most clearly shown at 45 in Fig. 4. Springs 43, 47, are considerably smaller than the remaining switching springs as will be readily clear from the illustrations 1n Figs. 2 and 4. It will thus be seen that when the plunger 32 is in the position shown in Fig. 4, the conducting ring 35 closes circuit between springs 43 and 47. New whenever the armature is attracted said conducting rlng opens the circuit between springs 43 and 47, but closes its circuit between springs 42, 44, 45 and 46. lt will also be noted that a jumper 48 electrically connects springs 43 and 44. The general construction of the device will thus be apparent to those skilled in the art.' By reason of the spring 3l a rather quick circuit change is E.

effected, thus securing a snap action movement.

Referring now more particularly7 to Fig. 6, which diagrammatically illustrates one forni of the many circuit arrangements to which my device is applicable, it will be seen that one terminal of the solenoid is connected to the spring 47 and the remaining terminal of the solenoids is connected to the right hand jack thimble 7. y

Mains 49 and 50 of the current supply clrcult are indicated. There is also shown a lamp 51 which is supposed to he in the nurses quarters, lamp which serves as the door lamp above the ward for instance from which the call has come, and lamp 53 which is a bed lamp and directs the nurse to the particular bed from which the call has come. The lamps have one or' their terminals all connected by way of the conductor 54 with the main 50. This same conductor 54 is also extended to connect with the left hand jack thimble 7. A conductor 55 connects the springs 43 and 44 with the main 49. Spring 42 is connected to the free position shown in Fig. 4, then springs t.

and47 are connected together. Thus if push button is actuated at that time a circuit will be established which can be traced from the plungergportion of the push button 13 by way of conductor 56, plug 10, right hand jack thimble 7, solenoids 22, spring 47, conductingA ring 35,'spring 43, jumper 48, spring 44, conductor 55, main 49 to the source of power and back by way of main 50, conductor 54, left hand jack 10, and conthimble 7, coperating plug ductor 57 to the spring portion o f the push button 13. Thus a circuit is established for the solenoids 22 whereb they attract their armature 24 to there y cause the plunger to assume its .alternative position.

The circuit through springs 47 and 43 is thereby broken and the solenoids are thereby denergzed. The amature 24 however remains in its attracted position as there is nothing tending to restore it. With this new estab ished for all three of the lamps 51, 52 and .53, the circuit for one of the lamps for instance being traced from main 49, via

conductor 55, s ring 44, condlicting ring 35,

spring 42, con uctor 58, lamp 53, conductor 54, to the main 50. Similarly the circuit for the lamps 51 and 52 is simultaneously established.

As readily understood a great many of these switches can be used to operate individual lights, and in addition to operate pilot lights2 for instance, the lamp 52 may be a pilot light for-the ward corresponding to a great many switches at .the different beds in the ward. It will thus be seen that my improved device is very flexible in that it permits of almost universal circuit interconnections for purposes such as these. The

device is applicable to both A. C. and D. C. circuits. l

Having thus described one embodiment of my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a device of the character described the combination with a supporting plate, an electromagnet having a pair of coils projecting backwardly from said plate, a pivoted armature mounted backwardly of said electromagnet, one end of said armature overlying said electromagnet, a push button projecting through said plate and adapted to coperate with the end of said armature overlying said electromagnet, said push button being unconnected to said armature, a rod carried bythe opposite extremity of said armature and having a` lost motion con-V nection therewith, a contact barrel carried whenever the plunger 32 is in the osition of the plunger 32 circuit is v by said rod, a contact ring carried by Said barrel, and long and short contact springs coperating with said barrel, said springs by their rictional engagement with said barrel holding said barrel at either end of its'throw, the springs of one length being adapted to vcontrol the 'circuit through said electroma-gnet and the springs of the. other length being adapted to'control signals.

2. In a device of the character described the combination with a vsupporting plate, an electromagnet having a pair of coils projecting backwardly from said plate, a pivotedl armature mounted backwardly of said `electromagnet, one end of said armature overlying said electromagnet, a push button projecting through said plate and adapted to coperate with the end of said armature overlying said electromagnet, said push button being unconnected' to said armature, a rod carried by the opposite extremity of said armature and having a lost motion connection therewith, said rod' being slidably mounted in said plate, a contact barrel carried by -said-rod, a contact ring carried by said barrel, and long and short contact springs coperati'ng with said barrel, Asaid springs by their frictional engagement with said barrel holding said barrel at eitherend of its throw, the springs of one length being adapted to control the circuit through said electromagnet and the springs of the other length being adapted to control signals.

3. In a device of the character described the combination with a supporting plate, an electromagnet having a pair of coils projecting backwardly" from said' plate, a ,piv oted armature mounted backwardly of said'l electromagnet, one end of said armature overlying said electromagnet, a pushbutton projecting through said late and adapted to coperate with the end) of said armature overlying-said electromagnet, said push but,- ton4 being unconnected to said armature, a rod carried by the opposite extremity of said armature and having a lost motion connection therewith, a contact barrel carried by said rod, a contact ring carried bysaid barrel, long and short contact springs cooperating with said barrel, said springs by their frictional engagement with said barrel holding said barrel at either end of its throw, the sprin v of one length being adapted to contro thev circuit through said electromagnet and the springs of the other length being adapted to control signals,

oted armature mounted backwardly of said 130 eleotromagnet, one end of said armature overlying said eleotromagnet, a push button projecting through said plate and adapted to coperate with the end ot' said armature overlying said eleetromagnet, said push button being unconnected to said armature, n rod carried by the opposite extremity of said armature and having a lost motion c011- nection therewith, said rod being slidably mounted in said plate, a Contact barrel carried by said rod, a Contact ring carriedl by said barrel, long and short Contact springs Coperating with said barrel, said springs by their friotional engagement with said barrel holding Said barrel at either end of miette its throw, the springs ofone length being adapted to control the circuit through said 

